1. Field of the Invention
In the use of polystyrene resins for making polystyrene film and foam polystyrene products, useful for making plastic wrappings, containers and the like, which are subsequently discarded, a litter problem may result even though such resins degrade slowly upon outdoor exposure (e.g., sunlight). Hence, it is desirable that such compositions be imparted with accelerated photodegradability characteristics to minimize or alleviate such problem.
The present invention relates to polystyrene-based compositions, e.g., general purpose polystyrene, that accomplish such a result by incorporation into said compositions a carbonyl-containing organic compound, as defined hereinafter, in a relatively small amount based on the weight of the accelerate and sufficient to accelerate photodegradability of the polystyrene. In a preferred embodiment, the invention relates to such compositions which additionally contain a relatively small amount of a prooxidant metal salt or an acetylacetonate of iron or cobalt thereby further enhancing photodegradability characteristics.
2. Description of the Prior Art
Polyolefin compositions (e.g., polyethylene, polypropylene, polybutene) and degradable films made therefrom containing, among other components, prooxidant metal salts of organic acids and metal acetylacetonates are disclosed in U.S. Pat. No. 3,454,510.
Compositions of benzophenone in blends with isotactic polystyrene, and results of studies thereon for crystallization kinetics are disclosed in an article (pages 885 and following) by Boon and Azcue in Journal of Polymer Science, Part A-2, Vol. 6 (1968).